THE man who caused the Long Flat crash that killed Gympie region cafe manager Karen Zahner in January 2018 has pleaded guilty in court.

Joshua-James Cameron Langley, 29, appeared in custody in the Gympie District Court yesterday on one charge of dangerous driving causing death or grievous bodily harm whilst adversely affected by an intoxicating substance on January 23.

He was formally arraigned on the matter and pleaded guilty to that charge.

Judge Glen Cash set the matter down for sentencing next Wednesday, February 5, bringing an end to a more than two year wait for Mrs Zahner's family.

Langley, who appeared in the courtroom dock dressed in prison greens, was remanded in custody until his sentencing date and was led from the courtroom by police after Judge Cash adjourned the matter.

A court spokeswoman confirmed Langley had been arraigned and pleaded guilty, and had been in custody on separate Magistrates Court matters since January 15.

The Gympie region community was left devastated by Mrs Zahner's death.

Reports at the time indicated Mrs Zahner, 59, was killed instantly and her husband, Bill, 64, left critically injured in the head-on impact.

Gympie police constable Ben Morrow said after the crash the two cars involved, a white Hyundai hatchback and a Ford Falcon sedan, had been travelling in opposite directions on a straight stretch of highway at Long Flat when they crashed just after 3.30pm on January 23.

Nambour senior constable Evan Condon confirmed the movements of the two vehicles before the impact on the Mary Valley Highway near Birt Rd.

"The Ford sedan travelling north (driven by a 27-year-old man) crossed into the path of the Hyundai (driven by Mrs Zahner)," Snr Cnst Condon said.

"The crash occurred in the southbound lane."